22 releases (4 stable)
2.0.0 | Sep 30, 2021 |
---|---|
1.1.0 | Sep 30, 2021 |
1.0.1 | Feb 12, 2021 |
0.5.11 | Jan 2, 2020 |
0.1.1 | Nov 28, 2019 |
#14 in #bit-field
78 downloads per month
Used in bitwrap
13KB
310 lines
BitWrap
BitWrap is a derive macro and trait to declare a struct data member with explicit size, in bits.
BitWrapExt Trait
Trait declares 2 methods:
fn pack(&self, dst: &mut [u8]) -> Result<usize, BitWrapError>
pack
method serialize struct fields into dst
array
fn unpack(&mut self, src: &[u8]) -> Result<usize, BitWrapError>
unpack
method deserialize struct fields from src
array
BitWrap Macro
use {
core::convert::{
TryFrom,
Infallible,
},
std::net::Ipv4Addr,
bitwrap::{
BitWrap,
BitWrapExt,
BitWrapError,
},
};
#[derive(Debug, PartialEq, Clone, Copy)]
enum Variant { Value55, ValueAA }
impl Default for Variant {
fn default() -> Self { Variant::Value55 }
}
impl TryFrom<u8> for Variant {
type Error = BitWrapError;
fn try_from(value: u8) -> Result<Self, Self::Error> {
match value {
0x55 => Ok(Variant::Value55),
0xAA => Ok(Variant::ValueAA),
_ => Err(BitWrapError),
}
}
}
impl TryFrom<Variant> for u8 {
type Error = Infallible;
fn try_from(value: Variant) -> Result<Self, Self::Error> {
match value {
Variant::Value55 => Ok(0x55),
Variant::ValueAA => Ok(0xAA),
}
}
}
#[derive(BitWrap)]
struct Packet {
// single bit field
#[bitfield(1)]
field_1: u8,
// bit field as boolean. 0 is false, otherwise is true
#[bitfield(1)]
field_2: bool,
// virtual field with option `name`
// unpack reads bits to the internall variable `_reserved`
// pack sets 6 bits from defined `value`
#[bitfield(6, name = _reserved, value = 0b111111)]
// use TryFrom<u8> for Variant
#[bitfield(8)]
variant: Variant,
// use TryFrom<u32> for Ipv4Addr
#[bitfield(32)]
ip: std::net::Ipv4Addr
// byte array
#[bitfield]
mac: [u8; 6],
// virtual field with optn `name` to define buffer length
#[bitfield(8, name = data_len, value = self.data.len())]
// get slice of `data_len` bytes and call BitWrapExt method for Vec<T>
// where T is u8 or with implemented BitWrapExt + Default traits
#[bitfield(data_len)]
data: Vec<u8>,
}
Dependencies
~1.5MB
~36K SLoC